Conventionally, there exists a first apparatus that has an antenna disposed forward of a vehicle for performing communications with vehicles in front or with roadside units (see Patent Document 1, for example). Specifically, a nondirectional antenna is disposed forward of an inclined line extending between the middle of a bar handle and the axle of a front wheel. This prevents influences of wave absorption by the rider's body, and prevents lowering of electric field strength in up and down and right and left directions.
Further, there exists a second apparatus that has a base in a storage box at the rear, and has a nondirectional antenna removably attached to the base (see Patent Document 2, for example). The antenna in this second apparatus is for receiving radio, and not for performing communications for an advanced safety vehicle ASV. However, a construction is employed to dispose the nondirectional antenna in the rear storage box.